For those who say there in no real intensity grading in GDS-2000E
This is an amplitude-modulated sine wave, right? So why is the curve with the lowest amplitude so much brighter than the others, and specifically brighter than the one with the highest amplitude?
It seems that, on the GDS-2000E, the brightness of a dot is a measure of
how long ago the dot was written to the display (consistent with the term "visual persistence oscilloscope" which GW Instek chose). In contrast, what I look for in an intensity graded display is that the brightness indicates
how often a dot is re-written. In the latter case, the minimum and maximum modulation curve should be of equal brightness in your example, I think.
I believe this difference is what others have also pointed out earlier in this thread, when they questioned whether GW-Instek has "real" intensity grading. I would also argue that GW-Instek simulates persistence, but not intensity grading (which enables discrimination of rare events from regular signals).